Out in the cold: polar animals - From zero to sixty (legs, that is)

Putting the science in fiction - Dan Koboldt, Chuck Wendig 2018

Out in the cold: polar animals
From zero to sixty (legs, that is)

By Brie Paddock

A hearty crew of adventuring space pirates, or gritty interstellar mercenaries, or tatty but idealistic rebels have just landed on a totally new planet. They crack open the airlock, stumble outside and find ... an entirely new world. Jungle? Desert? Savannah?

Or, better yet, ice.

Ever since Hoth in the 1980 movie The Empire Strikes Back, ice planets have popped up in popular science fiction films and books to challenge the protagonists with their bitter winds, barren landscapes, and the threat of frostbite. Maybe it’s the call of the poles on our own planet—so far, distant, and mysterious—that drives readers and writers to explore these icy extremes of light and dark.

As a kid growing up in Alaska, these frozen literary landscapes appealed to me immensely. But so often, the depictions of these Arctic-like wildernesses were peppered with small inaccuracies that rang false. Mostly, that the Arctic (or Antarctic) is an empty, barren landscape waiting to challenge protagonists. I missed the ravens cackling, massive herds of wandering caribou, tenacious mountain goats, vicious and solitary wolverine. Stunning flocks of migratory tern and geese, showing up as the days stretch to impossible lengths, like tourists wandering off of cruise ships.

Let’s face it, folks. There’s more to polar landscapes than ice and glaciers. Let’s talk about cold-adapted animals. Maybe you can add some of these ideas to your next climate fiction or space opera.

Heat is the name of the game

Most animals that successfully live at the poles are warm-blooded, or endotherms. They spend huge amounts of energy keeping their bodies warm, and most adaptations to the polar environment center around the production or conservation of heat: polar bears, musk oxen, walruses, orcas (killer whales), puffins, penguins. Thus, the poles have mostly been colonized by mammals and birds, the two major groups of warm-blooded animals (polar fish being the notable exception). But unless you’re working out the next Antarctic mermaid adventure, this may be a little far afield. (Though if you are, message me. We could totally chat.)

Bigger is better

Polar animals are big. Bigger than their warmer-adapted cousins, with fewer surface extensions (think ears, fingers, toes). This larger body size helps them hold a lot of body heat inside, as they’re constantly surrounded by the challenge of the cold environment. Physiologists call this Bergmann’s rule. You can call it whatever you want, as long as you have really, really large animals in your frigid environments.

Polar bears are the biggest of the bears. Arctic hares are larger than other jackrabbits, and their shorter ears and legs give less surface area for losing heat to the cold, cold Arctic winters. Orcas, which most people call killer whales, are actually dolphins. The largest members of the dolphin family, to be precise.

Never enough fluff

Insulation provides an important and necessary layer to trap all that body heat inside. Fluffy polar bears, fluffy seals, fluffy Arctic foxes, fluffy and waterproof sea otters. Only mammals have hair, but birds manage fluff with dense layers of feathers that can be extended. Penguins, ptarmigan, and puffins, which are all year-round residents at the poles, can extend their feathers to a thickness that would shame your favorite North Face jacket.

Insulation isn’t just fluff. Some marine mammals rely on dense coats of fur (and some have been hunted nearly to extinction for them), but others rely on other insulation. Blubber. Fat is a fantastic insulator, used by walruses, seals, and whales to fantastic effect, as well as woolly bear caterpillars and their fluffy setae (we’ll talk more about these lovely guys in just a minute).

Coloration is more than camouflage

White polar bears. White ptarmigan. White Arctic foxes. It’s easy to chalk their coloration up to snow camouflage and move on to the next phenotype. But white reflects heat energy, and there’s little enough to be had at the poles. So, a white coat reflects back the little heat energy provided by the sun at the poles, rather than absorbing it. But ... this white fur also reflects back heat energy given off by the body of the animal itself. So, white coloration provides good camouflage and also helps to trap body heat next to the skin. Polar bears take this one step further, having black skin that helps absorb that reflected heat energy.

Dens, burrows, homes

Most successful polar animals don’t spend the majority of their lives basking in the snow. Many extend their own insulation by seeking or creating microclimates—burrows or dens in which they sleep, hibernate, and bear young. The dens of polar bears, for example, can be extensive, multi-room dwellings that remain many degrees warmer than the outside environment. Arctic fox dens are similarly extensive, and families pass them down through generations. Some are centuries old and recent evidence suggest that, in the summer, these dens are the sites of fantastic wildflower growth in the tundra.

Including den-building capabilities in the next Arctic animal would give them an air of realism, but the dens themselves provide a wealth of opportunities for adventurers to stumble out of the cold.

Cold-blooded survivalists

While most polar animals are warm-blooded, let’s not forget about the Arctic woolly bear moth. This little bug takes seven to ten years to get through the caterpillar stage, because that’s how long it takes to get enough plant food to fuel its transition into adult moth. In between the few weeks of feeding opportunity provided by the brief summer, these caterpillars hibernate in shared cocoons. Travelers through deep space in cryo-freeze could learn a thing or two from the woolly bear moth.

Cryoprotectants

Antifreeze chemicals. They need them, they’ve got them. And by them, I mean cold-blooded animals that live near the poles. These chemicals, found in the blood (or other body fluids) of insects, worms, and fish near the poles, protect the organs and tissues of these animals as they freeze. These chemicals can work a little like salt in boiling water for pasta. But, instead of changing the boiling point, they decrease the freezing point so the organs and tissues of the animals freeze at a much lower temperature.

Mapping and navigation capabilities

Extreme climates shape more than physical features. Many polar animals have excellent mapping and navigation capabilities different from their temperate cousins. Imagine a Weddell seal, spending hours scouring the frozen Antarctic Ocean for food, trying to remember where he left his breathing hole. Rather more dire consequences if he fails than when we wander around the mall parking lot. Similarly, polar bears or Arctic foxes searching for their dens in the white expanse of snow can hardly rely on regular landmarks to find their way home.

Not all polar animals are residents. Many, especially birds and marine mammals, migrate to polar areas to feed in the summers. Migratory animals that find the same tiny island in the middle of the circumpolar seas also use amazing navigation capabilities in their thousand-mile-long journeys.

These evolutionary pressures have resulted in incredible mapping capabilities in the brains of most polar adapted animals, whether they’re year-round residents or migratory tourists.

In short, intrepid adventurers trapped on a frozen planet needn’t be alone. While Arctic-like landscapes may appear barren at first glance, there are a multitude of well-insulated animals lurking in warm dens just under the surface. Some may be frozen solid, some may have wondrous new antifreeze chemicals in their blood, while others may have thick, warm coats rivaling any man-made insulation. I look forward to seeing what new animals you use to populate your snowy landscapes.

Write well, my friends. Winter is coming.